23年 4月 19日 1

Overview of CR and DR

Gyeongsang National University Hospital Department of Diagnostic Radiology Radiation Technologist: You Dai In

23年 4月 19日 2

Direct Radiography (DR)

Overview of DR systemsCCD based systemsTFT + PhosphorTFT + Photoconductor

23年 4月 19日 3

Detector technology:CCD based systemsA. Lens Coupling B. Fiber optic coupling C. multiple detectors

A phosphor screen converts X-rays into visual light that is projected onto a CCD or onto a CCD-array

23年 4月 19日 4

CCD based systems

Company Imix Swissray TrexTechnology RED - Agfa

GOS:EuGOS:Tb4 CCD’s

CsI + FOP12 CCD’s

Application Chest General Mammo fullfield

Active Area 15.7”x15.7” 14” x 17” 8” x 10”

FDA clear. Yes yes no

MarketingStrategy

DealersDistributors

Directsales

OEM FisherLorad

• Mature technology• Mostly dedicated applications: mammography, chest• FDA approved except for mammography

23年 4月 19日 5

Detector technology:TFT + Phosphor

Photodiode convertsvisual photons into electrons

Electrons are stored oncapacity of switching element

Phosphor

Phosphor screenconverts X-ray photonsinto visual photons.

23年 4月 19日 6

TFT + PhosphorCompany Canon dpiX GE Trixell

Technology GOS:Tb GOS:Tb CsI:Tl CsI:Tl450µ

Application General General General,Mammo

General

Active Area 17”x17” 11.5”x15” 41x41cm19x23cm

15.7”x15.7”

FDA clear. yes OEM yes yesMarketingStrategy

OEMDirect Sales

OEM GE OEM

• GOS systems: available on the market• CsI systems: limited availability• FDA approved

23年 4月 19日 7

Detector technology:TFT + Photoconductor

Electrons migrate to surface electrode

Electrons are stored oncapacity of switching element

Charge transport in photoconductor

23年 4月 19日 8

TFT + PhotoconductorCompany dpiX Noranda Hologic Toshiba

Technology PbI2 100µ -Se 200µ -Se 500µ -Se 1000µApplication Mammo

FluoroMammo Spot General Fluoro

AngioActive Area 50x50mm2 90x90mm2 14” x 17” 7.5” x 9.5”FDA clear. Experimental Experimental Yes ExperimentalMarketingStrategy

OEM

Experimental except Hologics

23年 4月 19日 9

Weaknesses of TFT systems Low yield of TFT array fabrication Ghost images

Charge trapping in amorphous semiconductors

Clustering of Tl+ dopant in CsI needles Limited dynamic range (a- Se) due to high

dark current Image deformation beyond w>Nyquist due

to aliassing (a-Se) Electronic noise in low dose applications Detector damage at high dose (capacitor

overload)

23年 4月 19日 10

Principle of CR

I 0I 00I I00 I0I 00 I I I0I II

Laser

Storage phosphor plate

Rollers

Light guide

Galvanometer

Photomultiplier

Electrical Signal

Digitisation

A/DA/D

23年 4月 19日 11

Computed RadiographyCompany Agfa Fuji Kodak Konica Lumisys

Technology BaFBr BaFBr BaFBr BaFBr BaFBr(Agfa)

Application General General General, General GeneralActive Area 14”x17” 14”x17” 14”x17” 14”x17” 14”x17”FDA clear. yes yes yes yes yesMarketingStrategy

DirectSales

DirectSales

DirectSales

DirectSales

DirectSales

• Mature and robust technology• FDA approved and clinically accepted for all applications except mammography

23年 4月 19日 12

CR and DR: EconomicsFlat Panel Investment $250-300K for

one room $100K to replace damaged

detector

DR 20% higher productivity

6 pat./h x 2exp./pat. x 10h/day x 200 days/yr = 24 000 exp/yr

1 room = 24 000 exp./yr Amortisation 5 yrs = 120

000 exp. $350 000 / 120 000 exp. =

$2.90/exp.

CR Investment $150K for 3 to

4 rooms $1K to replace damaged

detector

CR productivity ~conventional

5 pat./h x 2exp./pat. x 10h/day x 200 days/yr = 20 000 exp/yr

3 rooms = 60 000 exp./yr Amortisation 5 yrs = 300

000 exp. $150 000 / 300 000 exp. =

$0.50/exp.

23年 4月 19日 13

CR/DR world market evolution 1996-

2005 19

96

1997

1998

1999

2000

2001

2002

2003

2004

2005

CR

DR

23年 4月 19日 14

Assumptions Penetration of digital acquisition in the x ray

rooms will evolve from 2.5% in 1999 to 11% in 2005

Within this digital segment, DR will substitute CR differently according to the application: Mobile: 100% retention of CR by 2005 Chest: 0% retention of CR General Rad high end: 70% retention of CR General Rad low end: 85% retention of CR

23年 4月 19日 15

CR and DRNew flat panel digital detectors are compact,

offer fast image acquisition and promise excellent image quality

DRFlat panel

CR

23年 4月 19日 16

Evolution of Digital Radiography Detector

23年 4月 19日 17

Innovation in Plate technology

Powder Phosphor BaFBr Needle Phosphor CsBr

“state of the art CR”more absorptionhigher sharpnesshigher image quality

23年 4月 19日 18

New CsBr:Eu PhosphorHigher image

quality Cubic crystal facilitates needle growth Equivalent specific X-ray absorption: ( =4.44 vs.

5.1 g/cm3)

Efficient stimulation with diode laser (stimulation 685 nm)

Efficient detection with PMT or CCD (emission 450 nm)

Excellent storage phosphor: Conversion efficiency > BaFBr:Eu

(more light / absorbed X-ray) Lower stimulation energy

Read-out requires 3 times less laser power

23年 4月 19日 19

DQE, 2,5 µGy (SC 400) 70 kV, 0.5mm Cu-Filter

0

0,2

0,4

0,6

0,8

0 1 2 3 4

Spatial frequency (Lp / mm)

DQE

CR "Needle IP", prototypemeasurement results

DR literature data (C. Chaussat etal., SPIE Med. Img. 1998)

CR, state of the art ("powder IP")

23年 4月 19日 20

Scanhead line scanner:Higher

throughput Fast acquisition (5s scan, 20s cycle) QE CCD > QE PMT Higher gain

Flying Spot Scanhead

Scan: pixel per pixel Scan: line per line Detector: Photomultiplier Detector: CCD

PhotoDetector

Fiber Optic Phosphor Image Plate

Galvo

Light Beam

Collimator

LaserScan-Head

SHT Phosphor Image Plate

23年 4月 19日 21

Scanhead - Scanning Principles

Front-StimulationFront-Stimulation

ADC StratusADC Stratus

Back-StimulationBack-Stimulation

CR PanelCR Panel

23年 4月 19日 22

Scanhead - 17” Front stimulation

23年 4月 19日 23

Scanhead - 17” Prototype(Back-Stimulation)

23年 4月 19日 24

Scanhead, the unifying technology

Scanhead Phosphor Image Plate

• simple• mature• robust• economic• multi-application

• fast• compact• integrated• higher image quality

CR

AGFA - Patent

(DR)

23年 4月 19日 25

Ideal DR System

23年 4月 19日 26

DR Detector Technologies

23年 4月 19日 27

CR and DR DQE

23年 4月 19日 28

DQE

23年 4月 19日 29

23年 4月 19日 30

Conclusions

The different technologies will coexist Best choice will depend on application CR potential is promising The difference between CR and DR

technology will become less relevant